Sleeve with widening taper at rearward end of bore

ABSTRACT

A block and sleeve assembly and a sleeve per se are disclosed. The sleeve has a central bore with a rearwardly opening taper. The holder block has a side-to-side opening with a bridge. An angle of the rearwardly opening taper and/or the distance from the beginning of the taper of the central bore of the sleeve to the surface of the side-to-side opening are sized to allow rearward removal of a shank of a sheared cutting pick from the sleeve. Optionally, an outer circumferential surface of at least a portion of the sleeve shank is forwardly tapered and the opening in the holder block is complementarily tapered to receive the sleeve shank. A rearward biasing retainer clip can also optionally be included.

FIELD

The present disclosure relates to a sleeve for a block and sleeveassembly. In particular, the sleeve has a central bore with a rearwardlyopening taper to allow rearward removal of a shank of a sheared cuttingpick from the sleeve.

BACKGROUND

In the discussion of the background that follows, reference is made tocertain structures and/or methods. However, the following referencesshould not be construed as an admission that these structures and/ormethods constitute prior art. Applicant expressly reserves the right todemonstrate that such structures and/or methods do not qualify as priorart.

Various different forms of equipment and machinery can be employed formining and excavation operations. Typically, it is the type of mining orexcavation taking place, and the type of earth being mined or excavated,that dictates the type of equipment and machinery that is appropriate.Commonly, equipment and machinery for such purposes include a cuttingpick mounted on a rotating element either directly or via a block or viaa block and sleeve assembly. In operation, the cutting picks rotate withthe rotating element to impact against and to dislodge or fragment earthfrom the face being contacted. Cutting picks employed for the abovepurpose generally have a hard cemented tungsten carbide tip, which isfixed, usually by brazing, to a head of the cutting pick, and a steelshank. Cutting picks of this kind are disclosed in various publications,such as U.S. Pat. No. 6,113,195.

Sleeved block systems can be press-fit in openings in holder blocks.However, press-fitting makes removing and installing sleeves in thefield very difficult and time consuming. Extreme force is often requiredto remove these sleeves from their holders. Hydraulic jacks aretypically needed to perform this task. In some operating environmentsthe use of hydraulic jacks or other equipment to remove press-fitsleeves is difficult and time-consuming.

As an alternative to press-fit systems, sleeve retaining methods havebeen used, such as clips, nuts or wedges in slots. Generally, nuts andwedges provide an advantageous biasing force to hold the sleeve in theopening. However, nuts are difficult to adjust and the slots for wedgesincrease manufacturing complexity and introduce a fracture generatinghole in the shank of the sleeve. Clips have provided a size restrictionto sleeve removal and are easily manipulated by a user, but have notgenerally provided a biasing force. A clip combining both a sizerestriction and a biasing force would be advantageous.

Another problem with existing sleeve designs is evident when aninstalled cutting pick breaks in the sleeve. Typically, it is the headof the cutting pick that shears off, leaving the shank in the bore ofthe sleeve. These broken pick shanks cannot easily, if at all, beremoved in the field while the sleeve is in the block due to limitedspace behind the sleeve and/or due to compacted debris in the block andsleeve assembly or even in open portions of the sleeve bore. Therefore,the sleeve with a broken shank must first be removed from the block inorder to remove the broken shank.

SUMMARY

An exemplary embodiment of a block and sleeve assembly comprises aholder block, and a hollow sleeve, wherein the hollow sleeve includes ashank portion, a head portion, and a shoulder portion, and a centralbore extending rearwardly along the central axis from a first opening ina forwardmost surface of the head portion to a second opening in arearwardmost surface of the shank portion, wherein the central bore hasat least two portions, a first portion of the central bore has a surfacelocated at a first radius and a second portion of the central bore has asurface with a rearwardly opening taper, and the first portion isaxially forward of the second portion, and wherein the holder blockcomprises a base portion and a body portion, a first opening extendinglongitudinally from a front face of the body portion to receive theshank portion of the hollow sleeve, a second opening extending from afirst side edge to a second side edge, and a bridge portion.

An exemplary embodiment of a hollow sleeve adapted to be mounted in aholder block and to receive a shank of a cutting pick comprises a shankportion, a head portion, and a shoulder portion, wherein the shankportion, head portion and shoulder portion are arranged longitudinalalong a central axis with the shoulder portion separating the shankportion from the head portion, wherein a central bore extends rearwardlyalong the central axis from a first opening in a forwardmost surface ofthe head portion to a second opening in a rearwardmost surface of theshank portion, and wherein the central bore has at least two portions, afirst portion of the central bore has a surface located at a firstradius and a second portion of the central bore has a surface with arearwardly opening taper, and the first portion is axially forward ofthe second portion.

An exemplary embodiment of an assembly comprises a holder block, ahollow sleeve, and a cutting pick, wherein the hollow sleeve includes ashank portion, a head portion, and a shoulder portion, and a centralbore extending rearwardly along a central axis from a first opening in aforwardmost surface of the head portion to a second opening in arearwardmost surface of the shank portion, wherein the central bore hasat least two portions, a first portion of the central bore has a surfacelocated at a first radius and a second portion of the central bore has asurface with a rearwardly opening taper, and the first portion isaxially forward of the second portion, wherein the holder blockcomprises a base portion and a body portion, a first opening extendinglongitudinally from a front face of the body portion to receive theshank portion of the hollow sleeve, a second opening extending from afirst side edge to a second side edge, and a bridge portion, and whereina shank of the cutting pick is inserted into the central bore of thehollow sleeve

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWING

The following detailed description can be read in connection with theaccompanying drawings in which like numerals designate like elements andin which:

FIG. 1 is a cross-sectional view of an exemplary embodiment of a blockand sleeve assembly.

FIG. 2 is another cross-sectional view of the exemplary embodiment of ablock and sleeve assembly shown in FIG. 1.

FIG. 3 is a cross-sectional view of an exemplary embodiment of anassembly showing the position of a cutting pick when installed in thesleeve bore of a block and sleeve assembly.

FIG. 4 is a cross-sectional view of an exemplary embodiment of a blockand sleeve assembly showing the rearward removal from the sleeve bore ofthe shank of a shorn cutting pick.

FIG. 5 is a schematic, isometric view of an exemplary embodiment of ablock and sleeve assembly utilizing an exemplary embodiment of aretainer clip.

DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of an exemplary embodiment of a blockand sleeve assembly. The illustrated block and sleeve assembly 2comprises a holder block 10 and a hollow sleeve 30. The holder block 10generally includes a base portion 12 and a body portion 14 and thehollow sleeve 30 generally includes a shank portion 32, a head portion34, a shoulder portion 36, and a central bore 38.

The holder block 10 can be any suitable holder block. In an exemplaryembodiment, the holder block 10 includes a first opening 16 extendinglongitudinally from a front face 18 of the body portion 14 to receivethe shank portion 32 of the hollow sleeve 30. The illustrated example ofa holder block is a bridge-type holder block and includes a secondopening 20 extending from a first side edge 22 to a second side edge 24and includes a bridge portion 26.

The hollow sleeve 30 can be any suitable hollow sleeve. In an exemplaryembodiment, the central bore 38 of the hollow sleeve 30 extendsrearwardly along the central axis A from a first opening 40 in aforwardmost surface 42 of the head portion 34 to a second opening 44 ina rearwardmost surface 46 of the shank portion 32. The central bore 38has at least two portions, the first portion 48 located axially forwardof the second portion 50. The first portion 48 has a surface located ata first radius R₁ and the second portion 50 has a surface with arearwardly opening taper 52 terminating at the second opening 44. Thesecond opening 44 has a second radius R₂, where the second radius R₂ islarger than the first radius R₁.

FIG. 2 is another cross-sectional view of the exemplary embodiment of ablock and sleeve assembly shown in FIG. 1. FIG. 2, among other things,shows the relationships between the rearwardly opening taper 52 andother features of the holder block 10 and the hollow sleeve 30. Forexample, the rearwardly opening taper 52 has a first end 54 and a secondend 56. The first end 54 has a smaller radius than the second end 56 andcontacts the first portion 48 at a transition plane P. The secondportion 50 of the central bore 38 is axially rearward of the shoulderportion 36, i.e., the transition plane P is axially rearward of theshoulder portion 36.

In another exemplary embodiment, an angle of the rearwardly openingtaper and/or the distance from the beginning of the taper of the centralbore of the sleeve to the surface of the side-to-side second opening inthe holder block are sized to allow rearward removal of a shank of asheared cutting pick from the sleeve. For example, an angle of therearwardly opening taper is suitably sized to allow, singly or incombination with the distance from the beginning of the taper of thecentral bore of the sleeve to the surface of the side-to-side secondopening in the holder block, rearward removal of the shorn shank. Anexample of a suitable angle θ of the rearwardly opening taper 52 is atleast about (±10%) 10° relative to the central axis A. Alternatively,the angle θ is from about 10° to about 45°, alternatively about 10° toabout 20°. In another example, a minimum distance from the first end 54of the second portion 50 of the hollow sleeve 30 to a surface 58 of thesecond opening 20 in the holder block 10 is suitably sized to allow,singly or in combination with the angle of the rearwardly opening taper,rearward removal of the shorn shank. The minimal distance is measuredalong the surface of the rearwardly opening taper 52 and a rearwardprojection 52′ thereof. An example of a minimal distance is equal to orgreater than an axial length L of the first portion 48 of the hollowsleeve 30.

The features and geometries of the central bore 38 can be manufacturedby any suitable techniques. In an exemplary embodiment, the central bore38 can be drilled or reamed, formed by other machining methods orforged.

Exemplary embodiments of the hollow sleeve optionally have at least aportion of an outer circumferential surface 60 of the shank portion 32forwardly tapered, alternatively all of the outer circumferentialsurface of the shank portion is forwardly tapered. The angle θ of theforwardly tapered outer circumferential surface 60 is at least about(±10%) 2° to about 15° relative to the central axis A. Alternatively,the angle θ is about 5° to about 6° relative to the central axis A. Asurface 28 of the first opening 16 in the holder block 10 iscomplementarily tapered to the forwardly tapered outer circumferentialsurface 60 of the shank portion 32. This taper provides optimal supportby distributing the load through the holder block 10. Although thisprovides a tight fit between the hollow sleeve 30 and the holder block10, the hollow sleeve can be easily dislodged, e.g., by a mallet strikeor a tool puller.

As illustrated in the figures, the first opening 40 can include a flaredor countersunk feature without impacting the operating principles of theblock and sleeve assembly 2 disclosed here. Such a feature canaccommodate, for example, a surface of the cutting pick or a washerassociated therewith, as shown in FIG. 3. Likewise, the second opening44 can also have a flared or countersunk feature.

FIGS. 3 and 4 illustrate a block and sleeve assembly 2 with a cuttingpick 100 installed therein. A rearwardmost end 102 of the shank 104 ofthe cutting pick 100 is positioned within the first portion 48 of thecentral bore 38. Alternatively, the rearwardmost end 102 of the shank104 can be co-terminus with the first end 54 of the second portion 50.During use, all or a portion of a head portion 106 or a head portion 106and a shoulder portion 108 of the cutting pick 100 can be shorn off,leaving the shank 104 installed in the central bore 38 of the hollowsleeve 30. Removing the shorn shank 110 can be time consuming ordifficult, even requiring removal of the sleeve before clearing of thebore can be accomplished. In addition, the second opening 20 in theholder block 10 and the second portion 50 of the central bore 38, e.g.,the portion of the central bore 38 not occupied by a properly installedcutting pick 100, collects compacted debris from operations. Thiscompacted debris further complicates the removal of the shorn shank 110by requiring the compacted debris to be cleared before access is gainedto the rearwardmost surface 46 of the shank portion 32 of the hollowsleeve 30 and to the rearwardmost end 102 of the shank 104 of thecutting pick 100.

FIG. 4 illustrates an example of removal of a shorn cutting pick shank.In the instant case, the sizing of the rearwardly opening taper 52and/or the minimum distance from the first end 54 of the second portion50 of the hollow sleeve 30 to a surface 58 of the second opening 20 inthe holder block 10 allows the shorn cutting pick shank 110 to be drivenrearwardly and out of the central bore 38. Driving of the shorn cuttingpick shank 110 can be by any suitable means, such as by a punch andhammer. The shorn shank 110, in addition to being driven rearward, canbe angled within the rearwardly opening taper 52 of the hollow sleeve 30and within the second opening 20 in the holder block 10 to facilitateremoval.

To provide sufficient retention of the hollow sleeve 30 in the holderblock 10, a retainer can be used. An exemplary retainer 120 is shown inFIG. 5, which also illustrates the retainer 120 installed in a retainergroove 122. The retainer 120 snaps into the groove 122 at the rear ofthe shank portion 32 of the sleeve 30 (see, e.g., FIG. 1) and provides aforce, urging the sleeve 30 rearward relative to the holder block 10 andinto the first opening 16 of the holder block 10. In an exemplaryembodiment, the retainer 120 is made from spring steel with a curvedprofile. When installed, the curved profile is positioned with theconcave portion oriented forwardly. The retainer 120 has a tab 124 witha slot 126 to assist with removal of the retainer 120 from the groove122.

In exemplary embodiments, the base portion 12 of the holder block 10 isadapted for mounting on a rotatable element of a machine for mining,excavating, tunneling, road planing and/or construction (not shown),such as an Alpine Miner mining machine available from Sandvik AB. Theholder block 10 has a large footprint providing ample weld surface area.It also has locating holes 130 in the base portion 12 (see, e.g., FIG.1), which can be used for easy alignment onto the machine.

The sleeve disclosed herein, and any associated holder block, can alsoincorporate rotation inhibiting cooperating features. An example ofrotation inhibiting cooperating features includes a polygon-shapedshoulder region of the sleeve that provides a flat, which contacts acorresponding surface of a stop on the block to prevent or limitrotation of the sleeve. The polygon-shaped head region of the sleeve isalso optionally inscribed within the shoulder of the pick, or washer ifused, which facilitates pick removal. Such cooperating features andoptional head region inscribed within the cutting pick shoulder aredisclosed in U.S. Patent Application No. 61/053,268, entitled “BLOCK ANDSLEEVE WITH ROTATION-INHIBITING FEATURE”, filed on May 15, 2008, theentire contents of which are incorporated herein by reference.

Although described in connection with preferred embodiments thereof, itwill be appreciated by those skilled in the art that additions,deletions, modifications, and substitutions not specifically describedmay be made without department from the spirit and scope of theinvention as defined in the appended claims.

1. A block and sleeve assembly, comprising: a holder block; and a hollowsleeve, wherein the hollow sleeve includes a shank portion, a headportion, and a shoulder portion, and a central bore extending rearwardlyalong the central axis from a first opening in a forwardmost surface ofthe head portion to a second opening in a rearwardmost surface of theshank portion, wherein the central bore has at least two portions, afirst portion of the central bore has a surface located at a firstradius and a second portion of the central bore has a surface with arearwardly opening taper, and the first portion is axially forward ofthe second portion, and wherein the holder block comprises a baseportion and a body portion, a first opening extending longitudinallyfrom a front face of the body portion to receive the shank portion ofthe hollow sleeve, a second opening extending from a first side edge toa second side edge, and a bridge portion.
 2. The block and sleeveassembly of claim 1, wherein the rearwardly opening taper has a firstend and a second end, the first end has a smaller radius than the secondend, and the first end contacts the first portion.
 3. The block andsleeve assembly according to claim 1 or 2 claim 1, wherein an angle ofthe rearwardly opening taper is at least 10° relative to the centralaxis.
 4. The block and sleeve assembly as in, claim 1, wherein thesecond portion of the central bore is axially rearward of the shoulderportion.
 5. The block and sleeve assembly as in claim 1, wherein atleast a portion of an outer circumferential surface of the shank portionis forwardly tapered.
 6. The block and sleeve assembly of claim 5,wherein an angle of the forwardly tapered outer circumferential surfaceof the shank portion is at least about 2° to about 15° relative to thecentral axis.
 7. The block and sleeve assembly as in claim 1, wherein aminimum distance from the first end of the second portion of the hollowsleeve to a surface of the second opening in the holder block is equalto or greater than an axial length of the first portion of the hollowsleeve.
 8. The block and sleeve assembly of claim 7, wherein the minimumdistance is measured along the surface of the rearwardly tapered sectionand a rearward projection thereof.
 9. The block and sleeve assembly asin claim 1, comprising a retainer groove in an outer circumferentialsurface of the shank portion and comprising a clip inserted into theretainer groove and biasing the hollow sleeve rearward relative to theholder block.
 10. A hollow sleeve adapted to be mounted in a holderblock and to receive a shank of a cutting pick, the hollow sleevecomprising: a shank portion; a head portion; and a shoulder portion,wherein the shank portion, head portion and shoulder portion arearranged longitudinal along a central axis with the shoulder portionseparating the shank portion from the head portion, wherein a centralbore extends rearwardly along the central axis from a first opening in aforwardmost surface of the head portion to a second opening in arearwardmost surface of the shank portion, and wherein the central borehas at least two portions, a first portion of the central bore has asurface located at a first radius and a second portion of the centralbore has a surface with a rearwardly opening taper, and the firstportion is axially forward of the second portion.
 11. The hollow sleeveof claim 10, wherein the rearwardly opening taper has a first end and asecond end, the first end has a smaller radius than the second end, andthe first end contacts the first portion.
 12. The hollow sleeveaccording to claim 10, wherein an angle of the rearwardly opening taperis at least 10° relative to the central axis.
 13. The hollow sleeve asin claim 10, wherein the second portion of the central bore is axiallyrearward of the shoulder portion.
 14. The hollow sleeve as in claim 10,wherein at least a portion of an outer circumferential surface of theshank portion is forwardly tapered.
 15. A machine for mining,excavating, tunneling, road planing and/or construction, comprising: arotatable element; and the block and sleeve assembly as in claim 1mounted on the rotatable element.